Crossposted from

TL;DR: Manifold Markets is:

Our story

We started with a crazy new twist on prediction markets. You come up with a question for traders to predict, and then decide the outcome yourself.

For example, you could create a market on “Will my date with [X] go well?” Anyone can bet on it, and the bets create a forecast on the chance your date goes well. After the date is over, you get to judge the result and reward the traders who picked the correct side.

There are so many ways for this mechanism to go wrong. The creator of the market can be dishonest in deciding the outcome, or you may just disagree with their resolution, with no recourse.

Nevertheless, we pitched user-created prediction markets in a grant proposal to the blog Astral Codex, without having any previous background in prediction markets, and somehow we won!

It’s been an exciting two months of us hacking away to realize this idea, and today, we’re happy to announce the official launch of Manifold Markets! We’ve gotten so much support from early users who are just as passionate about prediction markets as we are.

You might ask: Is there a reason to create a prediction market, and not a Twitter poll? Are outcomes really that different from a simple person-by-person vote?

Yes, I believe so. The magic driving prediction markets is accountability. When wagering a scarce currency, those proven right live on to make future bets, whereas those with less-savvy bets have their influence diminished. Prediction markets succeed because they reward accuracy, and that makes all the difference!

Our goal is to make prediction markets an order of magnitude easier for you to create and share. It should be as frictionless as a Twitter poll. As part of that philosophy, we’re launching with a play money currency, which we believe is just as fun and predictive.

We’ve already built up a passionate community of predictors and market creators, including writers like Richard Hanania and James Medlock, who have predicted everything from CDC recommendations to newsletter subscriptions to fatal shark attacks.

There’s so much unexplored space to ask questions and get valuable forecasts. For example, with conditional markets, you can create several related markets that help you make a choice based on which has the highest likelihood of success!

I’m excited to see what you all come up with. Go forth, create questions, trade on them, and predict the future!

- James from Manifold, along with cofounders Stephen and Austin

So how is Manifold different than Metaculus, Kalshi, PredictIt, etc.?

1. Anyone can come onboard and create a market

Existing prediction markets are very centralized; a core team of moderators decide what questions to ask. Occasionally they’ll solicit user suggestions, but as Scott Alexander put it:

Imagine if you could only tweet by emailing Jack Dorsey and convincing him that your comment was a good thing to have on Twitter. Even if Jack had good judgment and approved most requests, this would be a long way from the limbic system < — > Send Tweet loop that real Twitter users know and love.

Manifold aims to be Twitter for prediction markets!


2. The market creator decides how the market resolves

Existing markets focus hard on having objective resolution criteria. This means that the questions people pose are very narrowly focused — think of the “drunk looking under the streetlights because that’s where it’s brightest.”

Instead, Manifold allows market creators to use their own judgement on how a market ought to be resolved. So a question like “Will I enjoy moving to Miami” is fair game! Of course, there’s a time and place for having an objective resolution mechanism. We believe putting one individual in charge simplifies the resolution process enormously even for more objective questions.


3. Play money - it’s free to join and trade

To get started in other prediction markets, you have to pull out your credit card and put down some real money to get started. This means that people put their money where their mouths are, but also adds real friction in getting started. With Manifold, you can start trading as soon as you sign in! As long as there’s a subset of players trading to win, we believe the market mechanism will lead to accurate forecasts.

I thought you were already public - why a launch now?

Our team subscribes to the “always be shipping” philosophy of product development. In the last two months, we’ve gone from “hm, that would be cool” to the entire platform you see today, iterating and getting community feedback at each step. But we haven’t yet taken the time to step back and announce our work to the world.

So think of this launch as a Schelling point, a coordinated time to come check out our site. It’s also our statement that Manifold is now polished enough for general public usage. Some of our newest additions in the last month:

  • Communities that identify markets tailored to your interests
  • Mobile-optimized experience for creating and browsing markets
  • Inline conversations with other market participants

If you’ve been curious about what Manifold offers, now’s the best time to try it out.

What’s next for Manifold?

We’ll continue to push the edge in forecasting by making prediction markets ubiquitous. We have a lot of improvements planned for our play money site, including tournaments with cash prizes! And you may (not) be surprised to hear that we’re planning an entry into the crypto space... Subscribe for updates in the months ahead!


We’ve received help in the form of feedback, suggestions, and monetary support from truly too many to name — but we’ll try anyways.

To our friends and family (Lawrence, Jack, Lynelle, Adi, James, John, Peter, Ida, Luke, Eric, Nick, Sinclair, and Bruce): thanks for your encouragement while putting up with our crappy prototypes!

To the forecasters we’ve spoken with (Zvi, Nuño, Lars, Richard, Nikos, Tamuz, Nathan, Ege, gbear605, alwaysrinse, Tetraspace, David, Ozzie, Trevor and Eli): thanks for gifting us with your time, attention, and advice. That’s real precious stuff!

To our funders and sponsors (Scott, Paul, Lars, Duncan, Jack, Andy, Tristan, Nathan, Luca, and Alexander): thanks for taking a bet on us, for the ultimate vote of confidence, for putting your money where your mouth is!

And of course, a massive thanks to all the market creators and traders on Manifold — without you, there would be no markets~

Sign up for Manifold here, and let us know in the comments if you have any questions, feedback, or suggestions!


New Comment
22 comments, sorted by Click to highlight new comments since: Today at 4:08 PM

I really hope we get a real-money version of this some day. I think the incentive problems might actually solve themselves. If something is at 90% and you resolve it negatively so you can cash in with your alt accounts, probably people will notice that you did that and stop participating in your markets. The only markets that get really big will be those created by people who have built up a reputation for fairness.

Whether reputation works may depend on the questions asked. Suppose I ask whether I will enjoy my trip to Miami, a question that may attract people who don't even know me but have been there and zhe outcome of which cannot be verified. If I can resolve such questions in a way that [edited:] allows me to cash in with my alt accounts, it will take a long time until people can get their suspicions probabilistically confirmed.

it will take a long time until people can get their suspicions probabilistically confirmed

Seems like people would just solve this problem by being distrustful (on these kinds of questions) by default. Question posers would bootstrap trust either via their pre-existing reputations, or by honestly resolving a bunch of easy-to-evaluate questions first.

I'm not sure I understand - are you saying that a subjective personal question is one where you'd be more tempted to resolve incorrectly (or delay resolution)? There's no clear benefit to the market creator of delaying a resolution (they can't spend the funds that are committed to the markets), but definitely you're taking on some risk that the market creator will insider trade or otherwise act unethically on their market.

Purely subjective personal questions are questions where others cannot check reliably whether you resolved in an "unfair" way. So reputation also does not work, at least it takes a lot of time.

I edited the text of my first comment, using the words from Daniel's comment. Maybe it's easier to understand now. 

Oh, yes, that's a fair point! I think personal questions may self-correct for this, because they'll draw in less interest and less volume compared to a general-interest question (so possible fraud on personal questions is less profitable). Creators may have more of an informational incentive to let personal markets work well?

But it is a good point, that personal questions are much harder to audit and thus contribute less to reputation; if we formalize a reputation system it's one factor to consider!

Thanks! A real money/crypto version of the Manifold is very high on our priorities as well; they do have their own challenges (regulation for real money, technical infrastructure for crypto), but we're optimistic about being able to solve them.

And the mechanism you describe around reputation for fairness is exactly how we expect things to play out! I do think some more work around surfacing some kind judgment metric could be useful (eg total amount fairly adjudicated) but we have more thinking to do. If anyone has thoughts on what reputational metrics could be useful, let us know!

I'm not sure a formal metric is necessary. Maybe you could just have a "controversy" page associated with each user, where people can complain about how particular questions were resolved, and e.g. post evidence like "An anonymous account bought $10k worth of No when the probability was at 92%, and then an hour later that day the question resolved Yes!" Someone who is really trying to scam people would probably pretty quickly accumulate a pretty damning controversy page that anyone could see at a glance was pretty damning.

The exception to this would be "grey area" questions where it totally is subjective how it should go. For those questions they can make profit via anonymous accounts without anyone being able to tell what's happening. But hopefully this isn't a huge deal. For comparison, people will resolve many grey area questions in a biased way anyway, e.g. "Will Trump attempt to illegally hold on to power if he loses the 2020 election?" would probably be resolved positive if a Democrat created the question and negatively if a Republican did. If the amount of bias/noise introduced by illicit profit-making is no bigger than the "baseline" amount of bias/noise inherent in the system, then maybe it's not worth worrying about.

Originally I was going to suggest paying the question creators 1% of the proceeds of each question. However I think that might not be necessary. They are getting rewarded by having their questions answered, after all.

We do actually pay out the question creators! Right now it's 4% of profits. We don't do a great job of making this understandable in the UI though - and predictably (heh) most of our creators are more interested in the question outcome than in earning transaction fees.

A controversy page is interesting - kind of like Airbnb or Amazon reviews, but on a seller rather than on a product.

This is one of those "could easily go wrong in any number of ways" ideas, but...

You could plausibly have reputation encoded in other prediction markets. Like, I create a market "will X happen?" and people don't know how much to trust me. A trusted user could create markets for any or all of

  • Will X happen? (Based on their own judgment, not mine.)
  • Will philh judge correctly whether X happened?
  • Conditional on X happening, will philh judge that X happened?
  • Conditional on X not happening, will philh judge that X didn't happen?

And people could look at those markets to guess how much they should trust me, and people who know something about me can play in them.

Though that first one could also be done with the motivation of getting the profits from the question, where people will prefer to play in the trusted user's market instead of mine, which seems maybe not great.

Haha, some of our users have already invented similar markets for seeing if a market will be resolved correctly (e.g. ). I think this is a pretty promising solution!

There's still some interface work for making these reputational markets more common and visible, though -- if a popular market is judged likely to be fradulently resolved, this should be very noticeable to a new user.

Kleros is another (crypto) solution for deciding in contentious cases; I believe Omen actually supports Kleros-mediated contracts as a fallback for their user-generated markets.

You can use Futuur for real-money markets! Btw they are planning to have user-generated markets as well

great idea! since my metamed days i’ve been wishing there was a prediction market for personal medical outcomes — it feels like manifold mechanism might be a good fit for this (eg, at the extreme end, consider the “will this be my last market if i undertake the surgery X at Y?” question). should you decide to develop such aspect at one point, i’d be very interested in supporting/subsidising.

Yes, that's absolutely the kind of prediction market we'd love to enable at Manifold! I'd love to chat more about specifically the personal medical use case, and we'd already been considering applying to SFF -- let's get in touch (I'm

Does anyone know why this is a thing:

Why is the "Payout at 91%" displayed as $99 instead of 0.91*102 ~= $93 (or lower if 4% is taxed to pay out the question creator)?

I don't know if this answers your question, but they have a technical guide here.

Great platform btw, I'm having a lot of fun with it!

[+][comment deleted]2y1